I didn’t realize that I’m old until recently.

You’d think that’s something a person would pick up on, his growing closer to death and all.

But I have a way of seeing myself as a 35-year-old whenever I’m in front of a mirror. It’s willful misperception, a matter of looking straight into the eyes, not dwelling on the gray hair, and avoiding staring at the neck region. (Why in God’s name don’t people warn you about what happens to the human neck past age 50?)

Overall, the old I look ain’t the old I feel.

For the record, I am 62, soon to be 63. It’s not retirement age, but no one is asking me to go skateboarding or skinny-dipping.

My doctor, who recently discovered I have prostate cancer, announced that it’s important to fight it because “you’re still a relatively young man.” I was so grateful for the phrasing, I vowed to send him some Einstein’s Bagels, which AARP discounts at 10 percent for 60-plusers.

Part of what made me recognize my growing seniority was the news that they’re doing Woodstock 50 this year. I was too young to attend the original festival. But now I’ve lived long enough to see promoters planning a concert that will feature Hot Tuna and Miley Cyrus on the same bill. Trippy.

Also, the announcement that Mick Jagger postponed the latest Rolling Stone concert tour for surgery kind of shook me. When he sang, “You can’t always get what you want, but … you just might find/you get what you need,” I don’t think he originally had a heart stent in mind.

Still, the event that cemented my acceptance of my imminent dotage was what I now think of as The Delaware Movie Incident.

My daughter and I were late to a film she wanted to see, and the guy in front of me at the box office, who’d already bought his ticket, was gossiping with the ticket agent and not moving along.

I grew impatient, then blurted out something like “Come on, man, you’re making us miss our movie.”

There were a dozen better ways to handle it. I lost my cool, and I was wrong.

But then the guy, in his late 30s, started erupting like a suburban Krakatoa, gesturing and cursing. I told him to watch his mouth in front of my kid. He said, “I’ll say whatever I want.”

Now, I’m from a time (the distant past, as we established) and a place (pre-trendy Brooklyn, before it got bloated with artisan breads and beer) in which neighborhood-knucklehead, blue-collar goombahs like me could never let something like that slide.

I stepped well into volcano boy’s blast radius and growled: “Walk away. Walk away now.”

He did. And I immediately felt bad because the guy was clearly scared. But then I heard him tell his wife as he retreated, “He’s just a crazy old man.”

Crazy. Old. Man.

There it was. My daughter, who is 15, was annoyed at my boorish behavior, and in no mood to offer sympathy. I absorbed the gut punch and found my seat.

Being age-outed so definitively was nothing I could prepare for. With a single sentence, the guy pierced a shield of self-delusion I’d carefully constructed over the last dozen years.

Since that day, I’ve considered drastic measures, like dyeing my hair. I used to do it in my early 50s, only I’d buy women’s hair products like L’Oreal because I figured the store clerk would think I was getting it for a wife or girlfriend.

But after a while, I stopped coloring the gray. It didn’t help when my then-4-year-old kid pointed at my unnaturally brownish-red locks and explained to a woman friend I had over: “My daddy dyes his hair. The box has a lady on it.”

Actually, the more I think about, the more I realize my dyeing days are done.

Because, even if I make my hair as dark as Mick Jagger’s, what do I do about the neck?

Alfred Lubrano is an Inquirer staff writer.